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Finding the Fourth Proportional to 209.35, 313.84 and 87.70

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Solution

The fourth proportional to 209.35, 313.84 and 87.70 is: 131.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.35 : 313.84 = 87.70 : x
  2. Step 2: Convert to fraction form
    209.35/313.84 = 87.70/x
  3. Step 3: Cross multiply
    209.35x = 313.84 × 87.70
  4. Step 4: Simplify right side
    209.35x = 27,523.77
  5. Step 5: Solve for x
    x = 27,523.77/209.35
  6. Step 6: Final answer
    x = 131.47

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.